diff --git a/tests/AvailableDidTest.php b/tests/AvailableDidTest.php
index 006be12..28c06ac 100644
--- a/tests/AvailableDidTest.php
+++ b/tests/AvailableDidTest.php
@@ -14,6 +14,16 @@ public function testAll()
         $this->stopVCR();
     }
 
+    public function testFilterByNanpaPrefix()
+    {
+        $this->startVCR('available_dids.yml');
+
+        $availableDidsDocument = \Didww\Item\AvailableDid::all(['filter' => ['nanpa_prefix.id' => 'eeed293b-f3d8-4ef8-91ef-1b077d174b3b']]);
+        $this->assertContainsOnlyInstancesOf('Didww\Item\AvailableDid', $availableDidsDocument->getData());
+
+        $this->stopVCR();
+    }
+
     public function testFind()
     {
         $this->startVCR('available_dids.yml');
diff --git a/tests/fixtures/available_dids.yml b/tests/fixtures/available_dids.yml
index 6160a33..60fa581 100644
--- a/tests/fixtures/available_dids.yml
+++ b/tests/fixtures/available_dids.yml
@@ -74,3 +74,34 @@
             Access-Control-Allow-Methods: 'GET, POST, DELETE, PUT, PATCH, OPTIONS'
             Access-Control-Allow-Credentials: 'true'
         body: '{"data":[{"id":"0b76223b-9625-412f-b0f3-330551473e7e","type":"available_dids","attributes":{"number":"16169886810"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/0b76223b-9625-412f-b0f3-330551473e7e/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/0b76223b-9625-412f-b0f3-330551473e7e/did_group"}}}},{"id":"b6db898e-5c40-40b2-9ee8-3847d5345435","type":"available_dids","attributes":{"number":"61872285223"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/b6db898e-5c40-40b2-9ee8-3847d5345435/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/b6db898e-5c40-40b2-9ee8-3847d5345435/did_group"}}}},{"id":"89ca2b0e-38eb-430b-a5b8-843e47e0239a","type":"available_dids","attributes":{"number":"19733247924"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/89ca2b0e-38eb-430b-a5b8-843e47e0239a/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/89ca2b0e-38eb-430b-a5b8-843e47e0239a/did_group"}}}},{"id":"859db73a-d2ca-4834-b975-9b7b831ea252","type":"available_dids","attributes":{"number":"19736095078"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/859db73a-d2ca-4834-b975-9b7b831ea252/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/859db73a-d2ca-4834-b975-9b7b831ea252/did_group"}}}},{"id":"1f3c4f6b-15f6-4992-877e-33cb62f3bb10","type":"available_dids","attributes":{"number":"19492034504"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/1f3c4f6b-15f6-4992-877e-33cb62f3bb10/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/1f3c4f6b-15f6-4992-877e-33cb62f3bb10/did_group"}}}},{"id":"857d1462-5f43-4238-b007-ff05f282e41b","type":"available_dids","attributes":{"number":"19492033398"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/857d1462-5f43-4238-b007-ff05f282e41b/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/857d1462-5f43-4238-b007-ff05f282e41b/did_group"}}}},{"id":"35666e83-2385-438a-bb6f-9477c88d99eb","type":"available_dids","attributes":{"number":"19492034515"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/35666e83-2385-438a-bb6f-9477c88d99eb/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/35666e83-2385-438a-bb6f-9477c88d99eb/did_group"}}}},{"id":"46198397-0fbd-43bd-8a39-31e8a40c09cc","type":"available_dids","attributes":{"number":"17024795477"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/46198397-0fbd-43bd-8a39-31e8a40c09cc/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/46198397-0fbd-43bd-8a39-31e8a40c09cc/did_group"}}}},{"id":"b156ef32-f578-462c-b842-9b84b087521b","type":"available_dids","attributes":{"number":"17024795341"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/b156ef32-f578-462c-b842-9b84b087521b/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/b156ef32-f578-462c-b842-9b84b087521b/did_group"}}}},{"id":"e61b3863-86e9-4126-80c9-32fa10acd832","type":"available_dids","attributes":{"number":"441322659027"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/e61b3863-86e9-4126-80c9-32fa10acd832/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/e61b3863-86e9-4126-80c9-32fa10acd832/did_group"}}}}],"meta":{"total_count":260747}}'
+-
+    request:
+        method: GET
+        url: 'https://sandbox-api.didww.com/v3/available_dids?filter%5Bnanpa_prefix.id%5D=eeed293b-f3d8-4ef8-91ef-1b077d174b3b'
+        headers:
+            Host: sandbox-api.didww.com
+            Accept-Encoding: null
+            User-Agent: GuzzleHttp/7
+            Accept: application/vnd.api+json
+            Content-Type: application/vnd.api+json
+            api-key: PLACEYOURAPIKEYHERE
+    response:
+        status:
+            http_version: '1.1'
+            code: '200'
+            message: OK
+        headers:
+            X-Frame-Options: SAMEORIGIN
+            X-XSS-Protection: '1; mode=block'
+            X-Content-Type-Options: nosniff
+            X-Download-Options: noopen
+            X-Permitted-Cross-Domain-Policies: none
+            Referrer-Policy: strict-origin-when-cross-origin
+            Content-Type: application/vnd.api+json
+            Vary: Accept
+            ETag: 'W/"1fb1c5dfd84b9a4f82f91d79bc34ae20"'
+            Cache-Control: 'max-age=0, private, must-revalidate'
+            X-Request-Id: 693d1853-b901-461e-b7b2-2dd44a7b9ae7
+            X-Runtime: '0.189704'
+            Transfer-Encoding: chunked
+        body: '{"data":[{"id":"aa13b01c-36c8-405c-b5a8-1427aa7966ea","type":"available_dids","attributes":{"number":"18649204444"},"relationships":{"did_group":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/aa13b01c-36c8-405c-b5a8-1427aa7966ea/relationships/did_group","related":"https://sandbox-api.didww.com/v3/available_dids/aa13b01c-36c8-405c-b5a8-1427aa7966ea/did_group"}},"nanpa_prefix":{"links":{"self":"https://sandbox-api.didww.com/v3/available_dids/aa13b01c-36c8-405c-b5a8-1427aa7966ea/relationships/nanpa_prefix","related":"https://sandbox-api.didww.com/v3/available_dids/aa13b01c-36c8-405c-b5a8-1427aa7966ea/nanpa_prefix"}}}}],"meta":{"total_count":1,"api_version":"2022-05-09"}}'